FR2583479A1 - CLUTCH WITH OIL CIRCULATION, IN PARTICULAR FOR A MOTOR VEHICLE - Google Patents

Abstract

THIS IS A CLUTCH CONTAINING, IN A CRANKCASE 10, AND EACH PROVIDED RESPECTIVELY ON EACH OTHER OF A FRICTION DISC 11, A PRESSURE PLATE 12A AND A REACTION PLATE 12B, WITH, AT THE BACK OF THE PRESSURE PLATE 12A, OIL CIRCULATION CHANNELS 57A. FOLLOWING THE INVENTION, THESE OIL CIRCULATION CHANNELS 57A BELONG TO AN OIL CIRCULATION CIRCUIT TO WHICH OIL CIRCULATION CHANNELS 57B ALSO BELONG TO THE BACK OF THE REACTION PLATE 12B. APPLICATION, IN PARTICULAR, TO OIL CIRCULATING CLUTCHES FOR PASSENGER VEHICLES.

Description

The present invention relates generally to clutches

  commonly called "wet" clutches, that is to say the clutches in which the friction disc (s) used are immersed in any suitable liquid, in practice oil. It is more particularly those clutches in which it is organized a systematic circulation of oil, for an easier evacuation, and especially faster, the heat energy dissipated during a commitment action or disengagement, especially when such actions succeed one another at short notice and / or that it is not a simple clutch cut, but a starting clutch, that is to say a clutch through which passes the entire engine torque from a more or less complete stop

of the equipment served.

  This is the case for example for motor vehicles with mechanical transmission, and in particular for passenger vehicles whose transmission includes,

  in addition to such a clutch, a variable speed drive.

  At each start, the heat energy to be evacuated is important, and if such starts become repetitive, without each time this heat energy is properly dissipated, the temperature of the whole can increase rapidly, at the risk of deterioration of the most fragile constituents, and, more specifically,

  a toasting of the friction liners concerned.

  To minimize this risk, it is known to use a plurality of friction disks, alternately

with intercalated discs.

  But the corresponding achievements necessarily have a significant axial size, which makes it difficult to install on passenger vehicles, the available location on them being

particularly measured.

  In French Patent No. 983,867, of March 31, 1949, it has been proposed, however, an embodiment

  monodisc, that is, an achievement in which-

  a single friction disc being used, there is provided, in a housing, each disposed respectively on either side of the friction disk, two generally annular plates, which, for the axial clamping of said friction disk, are mounted axially movable relative to each other, and one of which, here said simply by convenience pressure plate, is subject to control means adapted to solicit towards the other, while said other tray, said here by simple convenience reaction plate, is adapted to provide axially support to the assembly. In practice, in this embodiment, and in a traditional manner, the reaction plate forms a relatively solid piece integral with the housing as well

  circumferentially than axially.

  Therefore, if it is possible to provide oil circulation channels on the back of the pressure plate, which are suitable for sweeping it with oil, this is not the case.

  not easily the same for the reaction plate.

  As a result, the cooling conditions of the friction disk are unevenly distributed on one and

the other side of it.

  Without further, it could result in a gradual degradation of the geometry of the friction disc, and uneven wear of the corresponding friction linings. In practice, in the embodiment described in this French patent, the friction disc used is not a traditional friction disc, that is to say a friction disc carrying the friction linings at the periphery of the his veil, but a particular friction disc. It is indeed a friction disk reducing to a veil, duly reinforced to oppose any deformation, and, together, the friction linings are worn, one by the pressure plate, the other by the reaction plate, being suitably

  and firmly subject to them.

  The present invention generally relates to a provision for the contrary to implement a traditional friction disc in a clutch oil circulation and further leading to other advantages. More specifically, it relates to an oil-circulating clutch of the type comprising, in a housing, each disposed respectively on either side of a friction disk, two generally annular plates, which, for clamping axial to said friction disc, are at least partly mounted axially movable relative to each other, and one, said by simple convenience pressure plate, is subject to control means adapted to solicit in the direction of the other, while said other plate, said by simple convenience reaction plate, is adapted to axially provide support to the assembly, with, on the back of said pressure plate, oil circulation channels, this clutch being generally characterized in that the oil circulation channels thus present on the back of the pressure plate belong to an oil circulation circuit to which also oil circulation channels on the back belong reaction plate. Thus, it is ensured a balanced cooling of the friction disk, that is to say a cooling is done in a comparable manner on one and the other of the faces of this one, and, therefore, this disk of friction can without inconvenience be a conventional friction disc,

  friction pads at the periphery of his veil.

  In practice, the control means associated with the pressure plate comprising elastic means, a piston mounted movably in the housing divides the internal volume thereof into two chambers, one hereinafter referred to simply as a hydraulic chamber, in which are located said elastic means, the other, hereinafter simply convenience mechanical chamber, wherein. the pressure plate, the friction disk and the reaction plate are located, with communication of these chambers to one another under the control of non-return means, the elastic means act on the pressure plate by means of intermediate of said piston, and the mechanical chamber, the one containing the pressure plate, the friction disk and the reaction plate, belongs to the oil circulation circuit, said mechanical chamber being itself divided into two parts by the one of said trays. In this way, the circulation of oil on the back of these trays is radially in one direction, for one of them,

  and radially in opposite directions, for the other.

  Such a circulation of oil is particularly favorable to the desired evacuation of energy

  heat dissipated on engagement or disengagement.

  Preferably, the reaction plate forms a part which, in the manner of the pressure plate, but without necessarily being axially movable like this, is free axially relative to the casing, while being

  suitably circumferentially wedged thereto.

  As a result, the oil circulation channels provided according to the invention on the back of this reaction plate can easily be formed between ribs raised projecting by said reaction plate and / or by the wall.

  cross section of the housing.

  The presence of these oil circulation channels

  does not imply any difficulty of manufacture.

  In practice, when the oil circulation channels present on the back of the reaction plate are thus formed between ribs projecting this reaction plate, the two pressure and reaction plates can advantageously be identical to each other. other, to the benefit, in particular, of a considerable reduction of

  corresponding manufacturing costs.

  Preferably, and according to a development of the invention, there is also provided a variable volume chamber, hereinafter simply for convenience modulating chamber, which, formed between two walls in cylinder-piston relationship with respect to the other, communicate

  with the mechanical chamber by flow nozzle means

  differentiated in the direction of movement, and which is axially inserted between the control means associated with the pressure plate and the transverse wall of the housing

  axially furthest away from the latter.

  Filled when the clutch is in the disengagement configuration, this modulation chamber is progressively emptied during its disengaged control, which advantageously ensures a progressivity of the latter. The characteristics and advantages of the invention

  will emerge from the description which follows,

  As an example, with reference to the accompanying schematic drawings in which: Figure 1 is an axial sectional view of a clutch according to the invention, for the disengagement configuration thereof; Figure 2 is, along the arrow II of Figure 1, and with tearing, a partial elevational view of a portion of the internal components of the clutch; Figure 3 is, supposedly developed flat, a partial view in circumferential section along the line III-III of Figure 1; Figure 4 shows, on a larger scale, the detail of Figure 1 indicated by a box IV thereon; Figure 5 is, along the arrow V of Figure 4, an elevational view of this detail; Figure 6 is an axial sectional view similar to that of Figure 1, for the engagement configuration of the clutch according to the invention; Figure 7 is also an axial sectional view similar to that of Figure 1, for an alternative embodiment of the clutch according to the invention; Figure 8 shows, on a larger scale, the detail of Figure 7 indicated by an inset VIII thereon; Figure 9 is a partial axial sectional view similar to that of Figure 7, for the engagement configuration of the clutch shown; Figure 10 is a partial axial sectional view which, similar to that of Figure 1, and limited to a portion of the internal components of the clutch according to the invention, relates to another embodiment; FIG. 11 is, supposed to be developed flat, a partial circumferential sectional view of this variant

  embodiment, along the line XI-XI of FIG.

  Overall, and as illustrated by these figures, the clutch according to the invention comprises, in a housing, and each disposed respectively on either side of a friction disk 11, two generally annular plates 12A, 12B which for the axial clamping of the friction disk 11, and according to the methods described in more detail later, are at least partly mounted

  axially movable relative to each other.

  According to modalities that will also be detailed later, the plate 12A, said simply by convenience pressure plate is subjected to control means adapted to solicit towards the other, while the latter, the plate 12B, said by simple convenience reaction tray, is suitable to provide

axially a support to the whole.

  In the embodiments shown, the housing 10, which is sealed, is formed of two shells 13A, 13B, each having a generally transverse wall 14A, 14B, and at the outer periphery thereof, a generally axial rim 15A, 15B, and which, their concavities being axially facing each other, are, by their axial flanges 15A, 15B, nested one inside the other and secured to one another, in practice by welding, the axial flange 15A of the shell 13A in practice covering at least part of the flange

B of the shell 13B.

  At its back, the transverse wall 14B of the shell 13B carries, projecting, on the one hand, in the vicinity of its periphery, a plurality of studs 16, which are appropriately distributed circularly, and by which, as shown in fine line in FIG. 1, the assembly can be fastened to a web 17 for rotationally securing it to a first shaft 18, in practice a driving shaft, and, axially, a stud 19, by which said assembly can also be centered on said tree, by

  engagement in a bore 18 'provided at the end thereof.

  This transverse wall 14B of the shell 13B is

full.

  On the other hand, the transverse wall 14A of the shell 13A is largely perforated, in its median zone,

through a central opening 20.

  In the embodiment more particularly shown in FIGS. 1 to 6, this central opening belongs in practice to a sleeve 21, which, distinct from the current part of the transverse wall 14A, is

  suitably reported sealingly thereon.

  In the embodiment shown in Figure 7, it belongs to the transverse wall 14A, the sleeve 21 then being integral with it. Nevertheless, and for reasons which will appear hereinafter, the opening 20 is circularly bordered, on the one hand, projecting axially outwards, by a flange 22, and, on the other hand, projecting axially inwards, by a flange 23 which extends along a circumference of lesser radius than

the previous.

  As schematized in fine lines in FIG. 1 by the flanges 22, 23 that the transverse wall 14A of its shell 13A thus presents, the casing 10 can be

  engaged, in practice sealing, on a fixed sleeve 25.

  It forms internally, between two cylindrical walls 26, 27 suitably sealed to one another, an annular space 28, which, via a conduit 29, can be connected to an oil circulation circuit, and which, by holes 30, is capable of communicating with the internal volume of the housing 10, said bores 30 opening substantially to the right of passages 31 that is present for this purpose, axially, between its flanges 22, 23, being properly distributed circularly , the transverse wall 14A of the

shell 13A of this housing 10.

  In practice, the transverse walls 14A, 14B of the shells 13A, 13B thus constituting the housing 10 are not flat, but, on the contrary, they each present

an axially stepped structure.

  The corresponding provisions falling within the skill of the art, they will not be described in detail here. The friction disc 11 is itself well known in

  self, and it will not be described in detail here.

  It will suffice to indicate that it comprises, transversely, a support web 32, which, at its outer periphery, and on both sides, bears friction linings 33, and which, by its inner periphery, is it -even worn, in practice via a torsion damping device 34 in the embodiments shown, by a hub 36. By this hub 36, and as shown schematically in fine line in Figure 1, the disk friction 11 is adapted to be wedged in rotation on a second shaft 37, in practice a driven shaft, which, substantially in alignment with the driving shaft 18, enters the housing 10 & favor the central opening 20 of the transverse wall 14A of the

shell 13A of it.

  In practice, there remains between this driven shaft 37 and the fixed sleeve 25, an annular space 38, which is coaxial with the preceding annular space 28, and which, like the latter, is adapted, by a conduit not shown, to to be connected to an oil circulation circuit, and is capable, by an annular passage 39 left free, at its end, between it and the hub 36 of the friction disc 11, to communicate, too, with the volume

internal housing 10.

  In practice, for reasons which will appear hereinafter, the shaft 37 of the friction disk 11 is tubular, said shaft 37 having an internal bore 40

  by which it opens into the internal volume of the housing 10.

  In the embodiments shown, the pressure plate 12A is monoblock, and it is reduced to a relatively massive ring with transverse faces

substantially parallel.

  It is mounted axially movable in the housing 10,

  while being wedged circumferentially on it.

  To do this, it is provided, in the embodiments shown, a tenon and mortise assembly

  between this pressure plate 12A and the housing 10.

  In practice, in the embodiments shown, this tenon and mortise assembly implements a plurality of tabs 42A which, provided radially generally projecting from the outer periphery of the pressure plate 12A, being properly distributed circularly, for example to 90 'two by two, meshing each with a groove 43A provided corresponding to the axial flange 15B of the shell 14B of the housing 10, the groove 43A, which extends axially, affecting in practice

  the entire thickness of said axial flange 15B.

  The control means associated with the pressure plate 12A thus constituted comprise means

elastics 44.

  It is a question, in the embodiments shown, of one or more conical washers of the type

Belleville washers.

  In the embodiment more particularly shown in FIGS. 1 & 6, and according to the methods described in more detail later, there are thus two

Belleville washers 45, 45 '.

  Anyway, the elastic means 44 thus constituting the control means associated with the pressure plate 12A do not act directly on it, but by means of a piston 47, which, mounted axially movable in the casing 10 shares the internal volume of the casing in two distinct chambers, one, 48A, hereinafter referred to simply as a hydraulic chamber, in which said elastic means 44 are located, and the other, 48B here referred to simply as a mechanical chamber, in which the pressure plate 12A, the friction disk 11, and the

reaction plate 12B.

  In practice, by the edge of its inner periphery, the piston 47 cooperates sealingly with the flange 23 which projects inwardly the transverse wall 14A of the shell 13A of the housing 10, and, by the edge of its outer periphery. it co-operates in sealing with a bearing of the axial flange 15A of this

shell 13A.

  It follows from the above that, through the passages 31 of the transverse wall 14A of the shell 13A, the hydraulic chamber 48A is in communication with the annular space 28 of the fixed sleeve 25, and that, through the annular passage 39, the mechanical chamber 48B is in communication with the annular space 38 formed, coaxially with the preceding one, about the shaft 37 of the friction disc 11, between said fixed sleeve 25 and said shaft 37. The hydraulic chamber 48A and the chamber mechanical 48B are further in communication with each other under

control of non-return means.

  In the embodiments shown, it is a plurality of nonreturn valves 50, which, suitably distributed circularly, are each individually implanted in a bore 51 of the piston 47, being arranged so as to allow circulation 48A hydraulic chamber oil to the chamber

  48B mechanical and & oppose reverse circulation.

  The mechanical chamber 48B is itself divided into two parts by one of the trays 12A, 12B, namely a part 52, which, as described above, is in communication, on the one hand, directly, with a first space annular, namely the annular space 38 formed around the shaft 37 of the friction disc 11, and, secondly, through the hydraulic chamber 48A and non-return means 50 controlling the communication between that and the mechanical chamber 48B, with a second annular space, namely the coaxial annular space 28 of the previous one, and a second part 52 ', which is in communication with the internal bore 40 of the shaft 37 friction disk 11, said internal bore 40 belonging to

  also to the oil circulation circuit.

  In the embodiments shown, it is the reaction plate 12B that provides this partition of the

mechanical chamber 48B.

  In practice, this reaction plate 12B comprises, on the one hand, a relatively massive peripheral portion 54, which forms the actual reaction plate, facing the pressure plate 12A, and, on the other hand, a central portion 55, which, secured to the previous one, tightly connects it to the shaft 37 of the disc of

friction 11.

  In practice, this central portion 55, made for example of stamped sheet metal, is crimped by its outer periphery to the solid peripheral portion 54 to which it is associated, and at its inner periphery it axially has a collar 56 by which it is

  engaged on the shaft 37 of the friction disc 11.

  Like the pressure plate 12A, the reaction plate 12B is free axially relative to the housing 10, while being circumferentially wedged thereto, but unlike the pressure plate 12A, and to be able to provide axially a support to the assembly, it is in axial support against the casing 10, and, in practice, against the transverse wall 14B of the corresponding shell 13B

of it.

  For the circumferential setting of the reaction plate 12B on the housing 10, there is provided a tenon and mortise assembly of the same type as that occurring between the pressure plate 12A and the housing 10, but with a circularly alternating arrangement of the tenons and

  corresponding mortises of one of said trays to another.

  This tenon and mortise assembly thus comprises, in the embodiments shown, a plurality of tabs 42B, which protrude generally radially to the outer periphery of the reaction plate 12B, being properly distributed circularly, for example at 90 two by two , and which meshes each with an axial groove 43B starting at full thickness the radial flange 15B of the shell 13B of the casing 10, the axial grooves 43B that thus has this axial flange 15B alternating circularly with those 43B corresponding assembly mortise and tenon intervening between the plateau

  12A and said housing 10, Figure 2.

  In practice, a clearance remains, at their outer periphery, between the plates 12A, 12B and the axial flange 15B of the shell 13B of the housing 10, as well, moreover, between the tabs 42A, 42B and the axial grooves 43A, 43B corresponding mortise and tenon arrangements, so that at said outer periphery of these trays 12A, 12B, the two parts 52, 52 'constituting the chamber

  mechanical 48B are in communication with each other.

  On the back of the pressure plate 12A are provided

57A oil circulation channels.

  In the embodiments more particularly shown in FIGS. 1 to 9, these oil circulation channels 57A are formed between ribs 58A projecting from the piston 47 to which the pressure plate 12A is leaned, said piston 47 being unable to then bear on said pressure plate 12A only by the crest zone of said ribs 58A, Figure 3, and said ribs 58A extend substantially radially. In any event, the oil circulation channels 57A thus present on the back of the pressure plate 12A belong, according to the invention, to an oil circulation circuit to which also 57B oil circulation channels belong. on the back of the tray

reaction 12B.

  In the embodiments more particularly shown in FIGS. 1 to 9, the oil circulation channels 57B thus provided on the back of the reaction plate 12B are formed between ribs 58B projecting from the transverse wall 14B of the shell 13B. corresponding case of the casing 10 to the right of the solid portion 54 of said reaction plate 12B, the latter can therefore bear on said transverse wall 14B only by the crest zone of said ribs

58B thereof.

  As previously, the ribs 58B thus has the transverse wall 14B of the shell 13 of the casing

  extend substantially radially.

  In practice, they are formed by stampings

  locally affecting this transverse wall 14B.

  As will become apparent hereinafter, the oil circulation circuit to which the oil circulation channels 57A, 57B belong is that to which belong, moreover, as already indicated above, the annular spaces 28 and 38, the hydraulic chamber 48A, the mechanical chamber 48B, and the internal bore 40 of the shaft 37 of the

friction disc 11.

  With regard to the oil circulation channels 57A, 57B, and as will appear later, the oil circulation is done radially in one direction, for one of the trays 12A, 12B concerned, and, after circumvention of these at their outer periphery, it is

  radially in the opposite direction for the other.

  In the embodiments shown, the clutch according to the invention also comprises a variable volume chamber 60, here referred to simply as a modulation chamber, which, formed between two walls in cylinder-piston relation with respect to to the other, communicates with the mechanical chamber 48B by nozzle means with differentiated flow rates in the direction of flow, and which is axially inserted between the control means associated with the pressure plate 12A and the transverse wall 14B of the housing 10 axially the farthest

of the last.

  In the embodiment more particularly shown in FIGS. 1 & 6, this chamber of

  modulation 60 is incorporated in the piston 47.

  In practice, this piston 47 forms by itself one of the walls delimiting the modulation chamber 60, and the other of the walls thereof is formed by an annular washer 61 slidably mounted in an annular recess 62, forming a cylinder, hollowed out in said piston 47 from the face thereof

  opposite the pressure plate 12A.

  At the same time, the differential flow nozzle means provided between this modulation chamber 60 and the mechanical chamber 48B comprise at least one flap valve.

reed 64.

  This is, as is best seen in Figures 4, 5, a tongue of metal or other which, disposed in the cylinder recess 62 of the piston 47, in contact with the bottom 65 of the recess 62 , is anchored, for example by a rivet 66, as shown, to said bottom 65, and whose free end has, at the right of an opening 67 passing right through the bottom 65 in question and thus opening into the chamber 48B, and more precisely in the portion 52 thereof, in one of the corresponding oil circulation channels 57A, an opening 68 of smaller dimensions than those of

the previous opening 67.

  In practice, at least a portion of the resilient means 44 constituting the control means associated with the pressure plate 12A bears on the ring washer 61 forming one of the walls which delimit the chamber of

modulation 60.

  For this purpose, in the embodiment shown in FIGS. 1 to 6, the two Belleville washers 45, 45 'constituting these elastic means 44

  are of radial extension and of different thickness.

  That, 45, which has the largest radial extension, and which, in conjunction with the illustrated embodiment, has the lowest axial thickness, is supported, by its outer periphery, on the transverse wall 14A of the shell 13A of the housing 10, through, in the embodiment shown, an annular support spacer 70, and, by its inner periphery, it bears on the piston 47 and, more specifically, on an annular boss 71 that has axially projecting for this purpose it in the direction of said transverse wall 14A,

  radially below the modulation chamber 60.

  Together, the other Belleville washer 45 ', which is therefore the one which has both the smallest radial extension and the largest axial thickness, is supported, by its outer periphery, on the previous Belleville washer 45, and, therefore, through it and through the annular spacer 70, on the transverse wall 14A of the shell 13A of the housing 10, and, by its inner periphery, it bears on the annular ring 61 forming one

  walls which delimit the modulation chamber 60.

  In use, and under the control of a distributor not shown, pressurized oil can arrive either in the annular space 28, through the conduit 29, or in the annular space 38, by a conduit not shown. For example, the pressure of this oil is

the order of 5 to 10 bars.

  When, as shown diagrammatically by arrows F1 in FIG. 1, it arrives through the annular space 38, the circulation in the casing 10 is as follows: By the annular passage 39, the oil reaches the mechanical chamber 48B, and, more specifically, the part 52 thereof, then, after licking the back of the pressure plate 12A, by circulating radially in a first direction, in the corresponding oil circulation channels 57A, it bypasses, at their periphery external, the pressure plate 12A and the reaction plate 12B, and it is then licking the back of the reaction plate 12B circulating radially, in the opposite direction to the previous, in the corresponding oil circulation channels 57B; it then leaves the housing 10 by the internal bore 40

  of the shaft 37 of the friction disc 11.

  Together, the oil thus circulated is prevented by the check valves 50 from gaining the

hydraulic chamber 48A.

  If, therefore, with the pressure losses close, it exerts then same pressure on one and the other of the faces of each of the trays 12A, 12B, it is not the same for the piston 47, which on one of its faces, the one facing the mechanical chamber 48B, receives the full pressure of the circulating oil, while on the other, that facing the hydraulic chamber 48A, it receives a zero pressure, this hydraulic chamber 48A then being in communication with the annular space 28, and, by

him, with a discharge.

  Thus, therefore, the piston 47 is discharged towards the transverse wall 14A of the shell 13A of the casing 10, until a balance is found between the forces of which it is the object, namely, of on the one hand, the hydraulic pressure on that of its faces which is turned towards the mechanical chamber 48B, and, on the other hand, the elastic force developed by the elastic means 45, on that of its faces which is turned towards the chamber

hydraulic 48A.

  The pressure plate 12A is thus not subject to any stress, the friction disc 11 is loosened, as shown, and the clutch concerned is

  so then in a state of disengagement.

  But, jointly, through the opening 67 of the piston 47 controlled by the reed valve 64, pressurized oil has invaded the modulation chamber 60, in the

  limits of the balance of forces mentioned above.

  Thus, for the disengagement configuration of the clutch, the elastic means 45 constituting the control means associated with the pressure plate 12A are counterbiased by the hydraulic pressure, partly through the single piston 47, and partly through this piston 47, the modulation chamber 60, and the annular ring 61 forming one of the walls which delimit it. It will now be assumed that, in response to an inversion of the control, the pressurized oil enters through the annular space 28, as schematized by arrows

F2 in Figure 6.

  The circulation of oil in the casing 10 is then

the next one.

  Through passages 30 and 31, the oil first enters, in this case, into the hydraulic chamber 48A, before gaining, through the non-return valves 50, the chamber

mechanical 48B.

  From its opening in the latter, its path is then the same as before: it licks the back of the pressure plate 12A, it bypasses the pressure plate 12A and the reaction plate 12B, it then licks the back of the tray. reaction 12B, and it leaves the housing 10 by the internal bore 40 of the shaft 37 of the

friction disc 11.

  Thus, with the charges close, the same pressure then exerted on either side of the piston 47, and the latter being no longer able to counteract the elastic means 44, these elastic means 44, thus released, can deploy their effects and solicit the plateau of

  pressure 12A towards the reaction plate 12B.

  But in practice, their intervention is then

in two times.

  At first, only the Belleville washer 45 comes in, the Belleville washer 45 'being still abutted by the oil in the chamber of

modulation 60.

  Overall, this intervention of the Belleville washer 45 is enough to bring the friction disc 11 to

  contact of the reaction plate 12B.

  As a corollary, under the pressure of the Belleville washer 45 ', the modulation chamber 60 progressively empties its oil through the nozzle 68,

  reduced opening of the reed valve 64.

  Once the oil thus evacuated from the modulation chamber 60, the Belleville washer 45 'in turn comes into action, adding its effects to those of the washer.

Belleville 45.

  There is then an effective clamping of the friction disc 11 between the pressure plate 12A and the reaction plate 12B, and the clutch is thus in the engagement position. It will be appreciated that, thanks to the modulation chamber, a certain progressiveness is introduced in this

  transition to the engagement position of the clutch.

  In the variant embodiment illustrated in FIG. 7, the modulation chamber 60 is incorporated in the

reaction plate 12B.

2 D83479

  It is therefore, in this case, by the annular washer 61 which forms one of the walls delimiting this modulation chamber 60 that the reaction plate 12B can bear on the transverse wall 14B of the shell 13B of the casing 10 and thus offer an axial support to the whole. As can be seen in FIG. 7, the stroke of this annular washer 61 in the corresponding recess 62 of the reaction plate 12B is limited, on the opposite side to the bottom 65 of said recess 62, by a stop 75 constituted by for example, and as shown, by a simple washer opened by a slot engaged with a

reaction plate throat 12B.

  Of course, this provision can also be

  adopted in the previous embodiment.

  In addition, in the embodiment shown in FIG. 7, an elastic washer 76, of the type

  Belleville washer for example, is provided between the ring.

  61 and the bottom 65 of the recess 62 of the plateau of

  reaction 12B, in the modulation chamber 60.

  Together, there is a stop of this plateau

  of reaction 12B in the corresponding axial direction.

  For example, and as shown, this stop is formed by a transverse shoulder 77 of the axial flange 15A

  of the shell 13A of the housing 10, FIG.

  Finally, in the embodiment shown, a single Belleville washer 45 is provided for the elastic means 44 constituting the associated control means

to the pressure plate 12A.

  For the rest, the provisions are of the type described above, and the operation is the same. In the variant embodiment schematically illustrated in FIG. 10, the fluid circulation channels 57A present on the back of the pressure plate 12A are formed between ribs 58'A which this pressure plate 12A projects, and likewise those, 57B, present on the back of the reaction plate 12B are formed between ribs 58'B which projects this reaction plate 12B. Thus, if desired, the trays 12A, 12B may advantageously be at least partly identical to one another, the pressure plate 12A may in practice be identical to the solid portion 54 of the tray of

reaction 12B.

  Of course, the present invention is not limited to the embodiments described and shown, but encompasses any variant embodiment and / or

  combination of their various elements.

  In particular, the oil circulation channels on the back of the pressure plate and the reaction plate may have any configuration, provided that they are able to ensure an oil circulation between the

  inner and outer peripheries of these trays.

Claims (19)

  1. Clutch with oil circulation of the type comprising, in a housing (10), each disposed respectively on either side of a friction disk (11), two generally annular plates (12A, 12B), which, for the axial clamping of said friction disc, at least partly are mounted axially movable relative to each other, and of which one, hereinafter simply for convenience pressure plate, is subjected to own control means & the to urge towards the other, while said other plate, hereinafter simply convenience -plateau reaction, is adapted to provide axially a support to all, with the back of said pressure plate (12A), oil circulation channels (57A), characterized in that the oil circulation channels (57A) thus present on the back of the pressure plate (12A) belong to an oil circulation circuit to which also belong channels oil circulation (57B) on the back of the reaction tray we (12B).   2. Clutch according to claim 1, characterized in that, the control means associated with the pressure plate (12A) having resilient means (44), a piston (47) movably mounted in the housing (10) shares the internal volume of the latter in two chambers (48A, 48B), one, hereinafter simply for convenience hydraulic chamber, in which are located said elastic means (44), the other, hereinafter simply convenience room mechanical, in which are located the pressure plate (12A), the friction disc (11) and the reaction plate (12B), with communication from one to the other of these chambers under the control of anti-friction means. return (50), the elastic means (44) act on the pressure plate (12A) via said piston (47), and the mechanical chamber (48B) containing the pressure plate (12A), the friction disc (11) and the reaction plate (12B) belongs to the oil circulation circuit, said chamber mec anique (48B) being itself divided into two parts (52, 52 ') by one of said trays (12A, 12B), so that the oil flow on the back of said trays (12A, 12B) is radially in one meaning for one of them and radially in opposite direction for the other.   3. Clutch according to claim 2, characterized in that, the friction disk (11) being wedged in rotation on a shaft (37), said shaft is tubular, its internal bore (40) belongs to the oil circulation circuit , and one of the parts (52, 52 ') constituting the mechanical chamber (48B) is in   communicating with said bore (40).   4. Clutch according to claim 3, characterized in that the other of the parts (52, 52 ') constituting the mechanical chamber (48B) is in communication, on the one hand, directly with an annular space (38) formed around the shaft (37) of the friction disk (11), and on the other hand, via the hydraulic chamber (48A) and the non-return means (50) controlling the communication between it and the mechanical chamber (48B), with another annular space (28) also formed around said shaft (37), coaxially with respect to the preceding one, both of said annular spaces   (28, 38) belonging to the hydraulic circulation circuit.   5. Clutch according to any one of   claims 3, 4, characterized in that one of the   trays (12A, 12B) comprises, on the one hand, a peripheral portion (54), relatively massive, which forms the actual tray itself, and, on the other hand, a central portion (55), relatively thin, which, solidary of the previous, tightly connects it to the tree (37) of the friction disc (11).   6. Clutch according to claim 5, characterized in that the plate which is thus in two   parts is the reaction plate (12B).   7. Clutch according to any one of   Claims 2 to 6, characterized in that it comprises a   a variable volume chamber (60), hereinafter referred to simply as a modulation chamber, which, formed between two walls in cylinder-piston relation with respect to each other, communicates with the mechanical chamber (48B) by nozzle means with differentiated flow rates in the direction of circulation, and which is axially inserted between the control means associated with the pressure plate (12A) and the transverse wall (14B) of the housing (10) axially the most away from it.   8. Clutch according to claim 7, characterized in that the modulation chamber (60) is incorporated in the piston (47), said piston (47) forming by   itself one of the walls that delimit it.   9. Clutch according to claim 8, characterized in that at least a portion of the elastic means (44) constituting the control means associated with the pressure plate (12A) is on the other walls   delimiting the modulation chamber (60).   10. Clutch according to claim 8, characterized in that said elastic means (44) having two washers Belleville (45, 45 '), one of them bears on the piston (47) and the other on the wall   concerned of the modulation chamber (60).   11. Clutch according to claim 7, characterized in that the modulation chamber (60) is   incorporated in one of the trays (12A, 12B).   Clutch according to Claim 11, characterized in that the modulation chamber (60) is   incorporated in the reaction plate (12B).   13. Clutch according to any one of   Claims 2 to 12, characterized in that the channels of   oil circulation (57A) present on the back of the pressure plate (12A) are formed between ribs (58A) which   protrudes the associated piston (47).   14. Clutch according to any one of   Claims 2 to 12, characterized in that the channels of   oil circulation (57A) present on the back of the pressure plate (12A) are formed between ribs (58'A) which   projecting door said pressure plate (12A).   15. Clutch according to any one of   Claims 1 to 14, characterized in that the channels of   oil circulation (57B) present on the back of the reaction plate (12B) are formed between ribs (57B) projecting from the corresponding transverse wall (14B). of the housing (10).   16. Clutch according to any one of   Claims 1 to 14, characterized in that the channels of   flow (57B) present on the back of the reaction plate (12B) are formed between ribs (58'B) which   protruding said reaction plate (12B).   17. Clutch according to any one of   claims I to 16, characterized in that   tenons and mortises of the same type are provided between the one and the other of the trays (12A, 12B) and the casing (10), with a circularly alternating arrangement of the tenons and mortises   corresponding to one of said trays & the other.   18. Clutch according to any one of   Claims 1 to 17, characterized in that the two   trays (12A, 12B) are identical to each other.   19. Clutch according to any one of   Claims 1 to 18, characterized in that the plateau of   reaction (12B) is free axially relative to the housing   (10) while being circumferentially wedged thereon.